David C. McCullough

Prognostic criteria for cerebrospinal fluid shunting from isotope cisternography in communicating hydrocephalus

IT IS WELL ESTABLISHED that ventricular filliiig in radioisotope cisternography provides reliable evidence of communicating hydro~ephalus.l-~ Numerous reports have shown that surgical shunting is highly beneficial in certain cases of adult communicating hydrocephalu~,5--~ although the prognostic criteria for surgical success have not been defined. Because of the need to avoid unnecessary and potentially hazardous surgery in patients with little likelihood of improvement, increased diagnostic accuracy is desirable. In reviewing the radioisotope cisternograms of patients with communicating hydrocephalus, we found poor correlation between ventricular filling alone and favorable response to shunting. However, where there was prolonged ventricular retention of the isotope, shunting proved successful in nearly every case. This suggests that cistemography possesses significant prognostic value in communicating hydrocephalus and may influence surgical decisions.

Symptomatic progressive ventriculomegaly in hydrocephalics with patent shunts and antisiphon devices

The antisiphon device (ASD) was designed to prevent excessive negative intracranial pressure and overdrainage with cerebrospinal fluid shunts. It has been recommended for prevention of slit ventricles and extreme shunt dependency. It was used by the author in 40 children and young adults who had low pressure headaches or were judged to be at risk for the development of subdural hematomas because of extreme hydrocephalus, relatively fixed head size, or tall stature. Nine patients encountered problems with adverse symptoms in spite of shunt patency. Four had alarming neurological symptoms of coma or severe headaches after incorporation of ASDs in ventriculoperitoneal shunt systems. With patients in the horizontal position, shunt patency was documented but computed tomography revealed progressive ventriculomegaly when they were kept erect. Symptoms abated and ventricular size diminished after conversion to proximal medium pressure diaphragm or spring-ball valve systems without ASDs. Because long shunt systems with ASDs require adequate hydrostatic columns to initiate flow when patients are erect, it is theorized that such symptoms could have been prevented by placing ASDs farther downstream from the cerebral ventricles.

Quantitation of Cerebrospinal Fluid Shunt Flow

A new method for quantitatively measuring flow through CSF diversionary shunts is described. Shunt reservoirs were injected with 0.05 ml 99mTcO4− and the clearance, λ, determined. The distribution volume of every known shunt reservoir was ascertained experimentally. CSF flow, F, was determined using the relationship F=λV. Good correlation between CSF flow and clinical outcome was found in 14 of 15 patients in whom shunt function was in question.

Large Arachnoid Cysts at the Cranial Base

Two infants who presented with macrocephaly had very large noncommunicating cysts at the cranial base that were displacing the brain. Only one of the patients was hydrocephalic; he eventually underwent ventriculoperitoneal shunting after craniotomy and attempted internal drainage of the cyst. The other infant had a cystoperitoneal shunt. Both have done well after 4 and 6 years of follow-up, respectively. These large arachnoid cysts are bilateral lesions with the potential for severe surgical complications and a questionable possibility of cure. The authors recommend systematic radiological investigation to decide the appropriate therapy, including an analysis of the patency of the subarachnoid pathways with radionuclide cisternography and cystography. Simple cystoperitoneal shunting may be the appropriate therapy for most of these large lesions. (Neurosurgery, 6: 76--81, 1980).

Present status of intrauterine treatment of hydrocephalus and its future

At a time when the intrauterine diagnosis of hydrocephalus is common and pioneering efforts of antenatal therapy are evolving, an assessment of intrauterine treatment of this disorder becomes pertinent. Consequently, the current status of the intrauterine treatment of fetal hydrocephalus is presented. The new data from the International Fetal Surgery Registry at the University of Manitoba in Winnipeg are discussed. The technical problems of antenatal shunting, the clinical trials, and experimental treatment are assessed. The prognostication and possible new approaches in intrauterine treatment of hydrocephalus are presented as well as the new diagnostic and surgical techniques. The outcome of the antenatal diagnosis and treatment of fetal hydrocephalus is evaluated.

Correlation between volumetric CT imaging and autopsy measurements of glioblastoma size.

A three-dimensional reconstruction and display technique (THREAD SYSTEM) for serial computed tomography (CT) was employed in monitoring tumor volumes in two children under chemotherapy for glioblastoma multiforme of the cerebral hemispheres. Progressive diminution of tumor bulk was documented in the first patient and an increase in volume in the second. The first patient expired of the complications of his therapy and the second of transtentorial herniation. Independent measurements of the tumors as determined by a CT scan near the times of death and tumor dimensions measured at autopsy revealed good correlations between the radiographic and the anatomical data. The final CT measurement of tumor volume of 20 cm3 compared with an autopsy calculation of 13.3 cm3 in the first case. In the second case, CT volume was 417 cm3 and the actual volume of the primary tumor mass at autopsy was 437 cm3. The results suggest that the THREAD system is a practical method for monitoring the results of radiotherapy and chemotherapy in certain types of cerebral neoplasms.

Surgical staging of cerebellar astrocytomas in childhood

Benign cerebellar astrocytomas of childhood, when removed grossly in toto, have high cure rates and thus can be staged by their surgical resectability. Currently, total tumor resection is limited by attachment to or invasion of the tumor into the brain stem or by evidence of recurrence or metastases. Tumors of the cyst‐nodule form are more often amenable to total gross removal because of their discrete margins and lateral placement, which is clear of brain stem structures. However, solid astrocytomas of the cerebellum, with or without visible cysts, may also be surgically cured if there is sufficient clearance from the brain stem. Patients with malignant astrocytomas of the cerebellum or metastases have much poorer prognoses. Preoperative and postoperative staging systems have been suggested based on these assumptions. Cancer 56: 1810‐1811, 1985.

Antenatal evaluation of fetal hydrocephalus with computed tomography.

Y. L., a 27-year-old black woman, para O-l-2-0, 39 weeks’ gestation by dates, was referred to our institution after a diagnostic ultrasound examination was suggestive of fetal hydrocephalus. The patient had received no prenatal care prior to 38 weeks’ gestation. Past history was significant in that she had given birth to a premature infant with microcephaly and hydranencephaly, who died 11 days after birth. Physical findings included a 28-week-size uterus with fetal heart tones present. The day after admission, an ultrasound examination showed a singleton fetus in breech presentation. The biparietal diameter was 10.4 cm, and neither the falx nor the lateral ventricles could be identified. The transtorso diameter

Computed cranial tomography and radionuclide cisternography in hydrocephalus

Computerized Cranial Tomographic scanning has replaced radionuclide cisternography in screening both adult and pediatric patients for hydrocephalus. Nevertheless, cisternography provides indispensable information about the CSF clearance capacity and remains a valuable adjunct to the excellent anatomic detail provided by CCT scans. In patients without emergency symptoms, cisternography provides the best indication as to whether or not diversionary shunting is likely to relieve the patients symptoms.

Radioisotope cisternography in the evaluation of hydrocephalus in infancy and childhood.

Investigations of patients with several types of hydrocephalus suggest that radioisotope cisternography can accurately determine the need for surgical intervention in mild cases and can differentiate patients with compensated (arrested) disease. In progressive communicating hydrocephalus, ventricular filling is commonly seen prior to shunting but is seldom found afterward. In noncommunicating hydrocephalus, patent subarachnoid pathways have been revealed in patients with normal cerebrospinal fluid pressure, suggesting that this technique may be helpful in predicting the most appropriate course of therapy.